Evaporative coolers have heretofore been constructed so that water which gravitates downwardly through an evaporative cooler pad has saturated material such as aspen fibers and air passing through the pad from the inlet side to the outlet side thereof has vaporized water and consequently attained an evaporative cooling of the air. During the gravitation of the water from the upper portion to the lower portion of the pad, the air passing through the pad tends to force the water toward the outlet side of the pad and causes a thinning of the saturated area of the pad near the lower portion thereof. Consequently, the vertical dimension of such pads has been limited to a size which does not promote undue thinning of the saturated area of the fibers of the pad near the lower portions thereof. Consequently, the overall capacity of evaporative coolers has been substantially limited relative to the horizontal cross sectional area of evaporative coolers which are usually in several forms, one of which is the conventional downward delivery type with evaporative cooler pad assemblies on four sides of the evaporative cooler. Others are of the side delivery type of which there are three evaporative cooler pad assemblies and one side delivery duct from the cooler for the delivery of evaporatively cooled air. It has been a problem, however, to obtain substantial capacity of an evaporative cooler without increasing the horizontal cross section of the cooler due to the fact that efficient operation of evaporative cooler pads is limited to a certain elevation in proportion to the thickness of the pad from the inlet to the outlet side thereof. Accordingly, prior art evaporative coolers have, of necessity, been somewhat limited in vertical dimensions of the evaporative cooler pad assemblies relative to the thickness of the pad assemblies from the inlet to the outlet sides thereof and such thickness is a factor related to the economy of initial production of evaporative coolers as well as replacement of such pads.
Prior art evaporative coolers have had enclosed top structures above the evaporative cooler water receiving trough areas and it has, therefore, been difficult to inspect the troughs to determine whether or not the water delivery is uniform and to thus maintain proper wetting of all of the pads in an evaporative cooler. The flow distribution of water in an evaporative cooler pad is extremely important due to the fact that dry holes may occur through which air may flow through the pads in the event portions of the pads are not properly wetted by suitable flow from the respective trough structures.
In accordance with the foregoing, it will be appreciated that large evaporative coolers have heretofore been of a large horizontal cross sectional area and have also required relatively thick evaporative cooler pad assemblies. Evaporative coolers of the large sizes have been used for cooling industrial buildings or the like, and the initial cost of such evaporative coolers, as well as the size thereof and the maintenance costs, have been substantial. From the foregoing, it will be appreciated that prior art evaporative coolers of different CFM capacities have employed evaporative cooler pads of many different lateral and vertical dimensions which has prevented standardization of one size of evaporative cooler pad for coolers of various CFM capacities.